Problem: Simplify. Rewrite the expression in the form $y^n$. $y^{-4}\cdot y^{3}=$
Recall that $x^n\cdot x^m=x^{n+m}$. $\begin{aligned} y^{-4}\cdot y^{3}&=y^{-4+3} \\\\ &= y^{-1} \end{aligned}$